TICKLE SENSATION — TIME
täte all that is heard (echolalia), or to mimic
the movements of others (echokinesis), and
so on. These impulses are closely allied to
the working of the Imperative Idea (q. v.).
The intelligence is not affected, and at times
intense effort may overcome the morbid tic ;
hut it is often a chronic and incurable dis¬
order.
Irresistible motor habits are termed con¬
vulsive tics, and the others psychic tics ; while
the more elaborate ones are termed co-ordi¬
nated tics.
Tic douloureux is an acute Neuralgia
(q. v. ) of the trigeminal or facial (fifth cranial)
nerve.
Literature : Noir, Etude sur les tics (1893).
(j.j.)
Tickle Sensation [ME. tiklen\ : Ger.
Kitzel ; Er. chatouillement ; Ital. solletico,
formicolio. A Touch Sensation (q. v.), whose
conditions are still obscure.
Tickling possibly includes a peculiar organic
quality derived from the unstriped muscles
that lie directly beneath the skin, and pos¬
sibly a circulatory quality (tingling and itch¬
ing : see Organic Sensation). Probably the
muscular movement is wholly reflex, and the
sense components in tickling are simply those
of light and intermittent touches and tem¬
peratures, with which visual or other associa¬
tions are conjoined. The muscular reaction
of laughter is intimately bound up with the
sensation.
Besides the well-localized tickle proper,
described above, there is a sensation-complex,
from rubbing and moulding the skin and
muscles, especially in certain regions (e.g. the
neck), which has very analogous, but more
massive, reflex effects. This is also called
‘ tickling,’ and is made use of in the games of
children. It has never been analysed.
Literature : Külpe, Outlines of Psychol.,
89, 147, 250; Sanford, Course in Exper.
Psychol., expt. 31 ; Hall and Allin, The
Psychol, of Tickling, &c., Amer. J. of Psychol.,
ix. 1897, 1. (E.B.T.-J.M.B.)
Tiedemann, Dietrich. (1748-1803.)
Born at Bremervörde and educated at Göttin¬
gen. In 1776 he became a teacher of ancient
languages at the Collegium Carolinum in
Cassel, in 1786 professor of philosophy and the
Greek language at Marburg, where he died.
Tilt-hoard: see Laboratory and Ap¬
paratus, III, B (c), (3).
Timbre : [Lat. tympanum, a drum, through
Er.]: Ger. Klangfarbe; Fr. timbre; Ital.
tirnbro. The complex of overtones and noise
that accompanies the Fundamental Tone
(q. v.) of a musical note.
It varies with the instrument, and thus
enables us to recognize the source of the
sound, as piano, harp, &c. It is sometimes
termed clang-tint or quality (Helmholtz, Eng.
trans., as below, Index, ‘ Quality ’) of a musical
tone. It would seem better, however, to
reserve the term quality for Pitch (q. v.).
Literature : Helmholtz, Sensations of Tone,
119; Sanford, Course in Exper. Psychol.,
expt. 90; Titchener, Exper. Psychol. (1901),
expt. 8. (E.B.T.-J.M.B.)
Time [Lat. tempus ; Gr. xp°vos] '• Ger.
Zeit; Fr. temps’, Ital. tempo. The measur¬
able form of continuity and externality of
parts in all real (empirical) process. Time is
constituted of the complex of relations of dura¬
tion and succession in the experienced order
of events. See Succession and Duration,
and cf. Change.
Time may be variously conceived, accord¬
ing to the point of view, as the order or
arrangement of existences in these relations,
as quantity or ‘ number ’ of changes relative
.to order of succession, and, again, as the ideal
‘ place ’ or medium in which these relations
of duration and succession are found. These
conceptions are general, applicable to an
indefinite number of instances. But all times
are commonly considered to be parts of one
unlimited time. This one single time, how¬
ever, is neither an individual conception nor
an ‘intuition,’ but an object to which the
general conception of time is applicable in
a special way. There is no ‘ intuition,’ i. e.
perception, of ‘ pure ’ time, and the only
way of representing it which is at all clear is
by the imaginary synthesis of moving points
or lines in space.
All accounts of time agree in connecting
it with change. A changeless content, like
a mathematical relation or a Platonic idea
or, in general, valid meaning or truth, is
not in time. But though change is essen¬
tial to time, time is not the mere qualitative
form of change. Nor is it mere succession or
the mere abstract relation of succession. For
succession to be temporal a relation of the
terms is required such as to form a continuous
and measurable series. The abstraction from
the content of the relation of before and after
in the continuity of a measurable process is
temporal succession. The abstraction from
the content of the total form of such a suc¬
cessive, continuous, and measurable process
is time. Time is thus both continuous and
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